PROBLEM 2. Differences Between Parents and Offspring 



Fig. 416 This is how Menders re- 

 sults with tall and short peas can 

 be explained. The small letter is 

 used for the gefie for shortness be- 

 canse the character is recessive. 

 How do all the offspring in the 

 (F^) lookF Are they pure or hy- 

 brid? What 5 kinds of offspring 

 appear in the (F^)? When (TT), 

 (ss), arid (Ts) were self -pollinated 

 to give an (F^) what kinds of off- 

 spring were produced by each? 



469 



of the Fo offspring. For example, when 

 the hybrid tall peas were crossed short- 

 ness segregated out in the F,; ss plants 

 appeared. 



We now think of the law of segrega- 

 tion in terms of genes and reduction 

 division and state it as follows: The two 

 members of a pair of genes separate or 



M tall }4 short 



segregate in reduction division without 

 having changed or contaminated one an- 

 other. When the hybrid Ts forms gam- 

 etes, some will have the gene called T, 

 some the gene called 5". Neither gene was 

 changed while associated with the other 

 in the hybrid plant. Try ^xercises i i 

 and 12. 



Fig. 417 Fr7iit shape has been studied in squash. 

 Is this dominance or blending inheritance? 

 Which law explains the offspring ifi the F,,.? 

 What might the genes be in the fiat F, squash? 



Fig. 418 Mendclian inheritance in rats. Which 

 coat color is dominant? Where does segrega- 

 tion show? (AMERICAN MUSEUM OF NATURAL 



history) 



